Australian world number two Adam Scott tightened his grip on the Arnold Palmer Invitational with another excellent round at Bay Hill in Florida on Saturday (AEDT).

Scott, at Bay Hill for the first time since he missed the cut in 2009, made six birdies and two bogeys on Saturday (AEDT) after the best first round in Bay Hill history to stand on 14-under 130 for 36 holes.

Scott began his second round with five pars before sinking a five-foot birdie putt at the par-five sixth, but found a bunker off the tee at the par-three seventh and made bogey.

The Australian closed the front nine with a 13-foot birdie putt and added back-to-back birdies at 11 and 12, sinking putts of five and six feet respectively.

Scott, 33, sank five putts from beyond 20 feet in round one on Friday (AEDT) and added a 28-foot birdie putt at the 15th on Saturday (AEDT).

After a tap-in birdie at the par-five 16th, Scott closed with a bogey, missing a five-footer for par at 18 to settle for a seven-shot lead entering the weekend.

American duo JB Holmes and Chesson Hadley and Italy's Francesco Molinari were the leading chasers back on 7-under 137.

In other Australian scores, Matt Jones (T29) was on 2-under after two rounds, Danny Lee (T39) was 1-under, Rod Pampling and Tim Wilkinson were 1-over, tied for 57th, while Marc Leishman and John Senden (T66), who won on the PGA Tour last week at Tampa Bay, were at 2-over.

Stuart Appleby finished at 3-over and Greg Chalmers ended the second round at 8-over. Both missed the cut.